Propeller



NOV. 13, 1.934,. Q HAV| 1 L Er AL 1,980,272

' PROPELLER Filed Jan. 27 1951 2 Sheets-Sheet l .R )Ll NvENTg? BYATTORNEY PROPELLER Filed Jan. 27, 1931 2 sheets-sheet 2 ATTORNEYPatented Nov. 13, 1934 UNITED STATES PATENT OFFICE PROPELLER Clinton HQHavill, South Orange, and Martin Mansson, East Orange, N. J., assignorsto Eclipse Aviation Corporation,

East Orange,

10 Claims.

' This invention relates to propellers and more particularly topropellers wherein the pitch of the blades may be varied duringoperation.

One of the objects of the present invention is to provide a propellerembodying novel mechanism for varying the pitch or angularity of theblades while the propeller is rotated.

Another object of the invention is to provide a novel pitch-changingrmechanism for a propeller which is automatically operable, thusdlspensing with the necessity of any manual control or adjustments.

Still another object is to provide in a variable pitch propeller, novelmeans for varying the pitch of the blades in accordance with the drivingtorque of the means or mechanism employed for rotating the propeller.

A further object is to provide in a propeller of the variable pitchtype, novel means responsive to centrifugal force for neutralizing thetorsion on the propeller blades and which cooperates with thepitch-changing mechanism for securing an efficient blade operating angleduring operation.

A still further object is to provide in a propeller, novel meansautomatically movable axially of the driving shaft for varying the pitchof the blades in accordance with the driving torque of the shaft,together with centrifugally-responsive means for substantiallyoffsetting the tendency of the blades to assume a zero-pitch conditiondue to torsion.

The above and further objects of the invention will appear more fullyhereinafter from the following detailed description when taken inconnection with the accompanying drawings. It is to be expresslyunderstood, however, that the drawings are for purposes of illustrationonly, and arenot designed as a definition of the limits of theinvention, reference being had for this purpose to the appended claims.

In the drawings, wherein similar reference characters refer to likeparts throughout the several viewsz- Fig. 1 is a horizontal partialsectional view of a propeller embodying the present invention;

Fig. 2 is an end view of the propeller, partly in section;

Fig. 3 is a side View, partly in section, taken on lines 3 3 of Fig. 2;and

Fig. 4 is afragmentary view in section of a portion of the propellerillustrated in Fig. 2.

Referring now to the drawings and more particularly Figs. 1 and 2thereof, a propeller embodying the principles of the present inventionis disclosed therein as comprising a plurality o f l propeller blades 6,a portion only of the blades being shown, in order to employ a largescale drawing. The blades are adapted to be rotated by a rotatabledriving shaft '7, which may be an engine crankshaft or extensionthereof, and the pitch of the blades is automatically adjustable inaccordance with the driving torque of the driving means '7, in a mannerWhich will appear more fully hereinafter.

In order to drivably connect the propeller blades 6 to the driving shaft7, there is provided a main hub forging 8 having a plurality of axiallyaligned sleeves or sockets 9, adapted to rotatably receive the root endsofthe blades. As shown, a driving block l0 is interposed between the huband driving shaft-secured thereto as by means of keys 11, and maintainedin proper relation with respect to the shaft by means of split front andrear cones l2 and 13 respectively, which are adapted to be brought intofirm engagement with said block by the provision of a threaded member ornut 14, threadedly received bythe outer eX- tremity of the drivingshaft.

Preferably, the hub 8 is drivably connected to the driving block andshaft so as to be axially movable in response to the driving torque ofthe latter and in the form shown, such drivable connection is effectedby any suitable means such as aplurality of helically or spirallyarranged ball bearings l0a which are interposed between the block andhub and are effective during torque-responsive movement of the shaft, toim-A part a longitudinal movement to the hub with respect to the shaft.

Means are provided for varying the pitch of the blades during suchtorque-responsive movement of the hub, and preferably such means areconstituted by cooperating members carried respectively by the drivingblock and the root ends of the blades. As shown, such means include apair of relatively stationary rack members 15, Fig. 3, xedly secured tolaterally extending ears 16, Fig. 2, formed integrally with a plate 17,the latter being rotatably mounted on the driving block 10 andmaintained in proper relation with respect thereto by means of a nut17a. Suitable thrust bearings 1'7b are interposed between memf bers 17and 17a in order to permit relative movement therebetween. Each of theracks is adapted to mesh with a ring gear 18, Fig. 2, secured, in anysuitable manner, to the root end of each blade so that during relativemovement between the hub and the driving shaft, these gears will lockedthereto.

travel along the racks 15 and effect a change in the pitch of eachpropeller blade.

In order to rotatably secure each blade in its respective socket, asplit sleeve 19 encircling the blade root end and secured thereon as bymeans of the ring gear 18, is provided, and these parts are firmlymaintained in proper position within the hub Asocket 9 by a member 20threadedly received by the outer portion of the socket and suitablyInterposed between the sleeve 19 and member I20, a ball thrust bearing21 is provided, and a suitable roller bearing 22 is confined between theinner portion of the hub socket and the ring gear 18 in order to permiteflicient and substantially frictionless rotation of the latter withrespect to the former.

Preferably, means are provided for yieldably resisting axial movement ofthe hub with respect to the shaft, and in the form shown such means areconstituted by a plurality of resilient members such as springs 23,which may be interposed between the plate 17 and the propeller hub. Itwill be apparent that the tension of springs 23 lis normally effectiveto maintain the hub in\such position relative to the driving shaft, thatthe pitch of the blades will be a maximum, as indicated by the bladesection 6a in dotted lines, Fig. 3, but vthat during operation, the hubwill be moved upwardly, as viewed in said figure, in response to thethrustof the propeller blades to compress the springs 23, thecooperation between 'the ring gear 18 and rack 15 being operable duringsuch movement to decrease the pitch of the blades. It is to beunderstood that the inclination or helical angle of the spiral ballraces 10 is such that the propeller hub vwill tend to move downwardly,Fig'. 3, in response to 4the driving torque of the engine shaft, toincrease the pitch of the blades, which movement opposes theabove-described thrust-responsive movement of the hub. Preferably, thesprings 23 are adjusted in such a manner as to be effective, duringoperation of the propeller, to arrest V the above-described Imovement ofthe hub in such a positionthat the resultant pitch will be substantiallyproportional to the driving torque of the drive shaft 7. y

Means is provided for substantially neutralizing or compensating for thetorsion of -each of the propeller blades and preferably, this 'means isresponsive to centrifugal force. .In the form of the inventionillustrated, such means is/constituted by counter-weighted gear segments24 adapted to cooperate with each respective ring gear 18 in such amanner as to tend to increase. the pitch of the blades, during rotationof the propeller, thus opposing the effect'of torsion which normallytends to decrease the pitch of the blades. Referring moreparticularly toFigs. 3 and 4, each counter-weighted gear. segment 24 is pivotallyconnected by a pin 25 lto a member y26, 'xedly secured to the hub socket9 as bymeans of screws 27. -Each hub socket is provided with a suitableslot in order to permit engagement between the segment 24 and the ringgear 18.

It 'will be apparent from the above that when the propeller is not inoperation, the resilient members 23 will be effective to maintainthe hubin the position shown in Fi'g. 1 wherein the pitch of each blade isamaximum. As soonas the driving means 7 is rotated in the desireddirection, l however, the hub will tend to be moved upwardly,

as viewed in Fig. 1, in response to thrust, and downwardly by reason ofthe screw-threaded 'action of the helically arranged bearingslOinterposed between the driving shaft and the hub, and the extent ofmovement of the latter, as

heretofore pointed out, will be-substantially pro- Y y portional to thedriving torque imparted to the vpropeller by the shaft 7. During suchmovement,

the pitch of each blade will be automatically 'varied because of thecooperation between the gear and rack members 18 and 15 respectively.

In the above described operation and considering that the propellerutilized is of the tractor type and normally rotating counterclockwise,as viewed from the front in Fig. 1, the spiral ball .races l0a arearranged similarly to a right-hand sponsive movement to the hub toproduce the desired change in pitch.

It is also to be pointed outl that the counterweighted gear segments 24constitutecentrifugally-responsive means which tend to increase thepitch of the blades and which oppose the effects of torsion which tendsto turn the blades into a zero-pitch condition. Referring to Fig. 3,when shaft 'l is rotated in a counter clockwise direction as viewed fromthe front, the segment 24 will tend to rotate in a clockwisedirectionabout the pivot 25, thus cooperating through gear 18 withv thestationary rack 15 and tending to force the hub downwardly, as viewed inthis figure, wherein the pitch of the blades will be a maximum.

There is thus provided by the present invention a novel propeller of thevariable-pitch type,

wherein the pitch of the blades is automatically controlled i'naccordancewith the driving torque of the means for .rotating thepropeller. The inclusion of the centrifugally-responsive meanscooperating with the pitch-changing mechanism in/ driving means and thehub,'an unusually efficient and substantially frictionless arrangementis secured for automatically moving said hub axially of the drivingmeans in response to the torque of the latten While there has been shownand described only one form of the invention, it is to be expresslyunderstood that the same is not limited thereto but may be embodied invarious mechanical forms in order to permit the use of a tractor orpusher vtype of propeller or to impart torque-responsive movement to thehub in order to produce the desired change in pitch during operation.

Various changes may also be made in the reladat tive sizes, shapes andarrangement of the various component parts of the invention withoutdeparting from the spirit thereof, as will lnow be apparent to thoseskilled in the art. Reference will therefore be had to the appendedclaims for a definitionof the limits of the invention.

What is claimed is: A

1. An. aircraft propeller, comprising a plurality of blades, drivingmeans therefor, means responsive to the driving torqueof said rst-namedmeans for varying the pitch of saidv blades, said for yieldinglycooperating with said torque-re-WLS( sponsive means, and means tocompensate for the torsion of the blades.

2. A propeller having a plurality of blades, a hub for receiving saidblades, means for rotating said hub, means responsive to the drivingtorque of said rotating means for moving said hub and blades relativelyto said rotating means, means for automatically varying the pitch ofsaid blades during such movement of the hub and blades, andcentrifugally-responsive means tending to oppose torsion of the bladesdue to centrifugal force.

3. In a propeller for aircraft having a plurality of blades, means forrotating said blades, means responsive to variations in the drivingtorque of said rotating means and including a gear and rack mechanismfor changing the pitch of said blades, and means responsive tocentrifugal force for neutralizing the torsion of said rotating blades.

4. An aircraft propeller having a plurality of blades, means forrotating said blades, means responsive to variations in the drivingtorque of said rotating means tending to increase the pitch of saidblades, and means responsive to centrifugal force tending to increasethe pitch of said blades.

5. In combination, a. rotatable shaft, a plurality of propeller bladesadapted to be rotated by said shaft, means responsive to variations inthe driving torque of said shaft for increasing the pitch of saidblades, yieldable means Vcooperating with said torque-responsive means,and means responsive to centrifugal force tending to increase the pitchof said blades.

6. A propeller comprising a plurality of pitchvariable blades, a hubtherefor, means for rotating said hub, resilient means for normallymaintaining the pitch of said blades at a maximum, and a helical drivingconnection between the hub and rotating means whereby said hub isrelatively angularly movable with respect to said rotating means inresponse to the torque of the latter and tending to increase the pitchof said blades in opposition to the thrust of the blades tending todecrease the pitch of the latter.

'7. In a propeller having a plurality of blades, means for rotating saidblades, means for automatically varying the pitch of the blades duringoperation, and. means including centrifugallyoperable counter-weightedgear members cooperating with said pitch-varying means for substantiallyovercoming the torsion of said blades.

8. In a variable pitch propeller, a hub, a plurality of propeller bladesrotatably carried by said hub, an engine driven shaft for rotating thehub,

means responsive to the torque of said shaft for.

moving the hub in one direction with respect to the shaft, meansresponsive to the thrust of the propeller blades for moving said hubl inanother direction with respect to the shaft, and means operated by amovement of the hub'in either direction to vary the pitch of the blades.

9. In a Variable pitch propeller having a pair of axially alignedsockets, a hub, a propeller blade rotatably mounted in each socket, arotatable power shaft, a helical driving connection between said hub andshaft, said hub being movable relative to the shaft in response to thedriving torque of the latter, means interposed between said shaft andsaid hub'and arranged forwardly of the latter for yieldingly opposingmovement of the hub in one direction relative to the shaft, and meansincluding elements carried by said shaft and blades respectively forvarying the pitch of the latter during torque-responsive movement of thehub relative to the shaft, said shaft carried elements extending intosaid hub sockets.

10. In a variable pitch propeller having a hub, a plurality of bladesrotatably carried by said hub, a rotatable shaft, means for drivablyconnecting said shaft and hub, said hub being movable relatively to saidshaft in accordance with the thrust of said blades and the torque ofsaid shaft, means interconnected between the shaft and blades forvarying the pitch of the latter during such relative movement of the hubwith .respect to the shaft, and weighted members cooperating with eachof said blades and responsive to centrifugal force for substantiallyneutralizing the effects of torsion on said blades.

CLINTON H. HAV'ILL. MARTIN MANSSON.

